This was using DDT4All 5.4.0 but I would suggest using the newest version you can download from Github.
Earlier versions of DDT4All may not have the correct buttons.

Also, depending on your car, DDT4All version, language settings, how you connect to
the car and the database you use, you may find the options are labelled differently.

Cruise Control/Speed Limiter Activation

Open the DDT4All program and connect to the car.

In box 2 on the left hand side, double click [AT] DCT453 VDIAG05_xx.xx.xx.ddt

In box 3 on the left hand side, double click Development.
This will open the option "Computer Configuration" just below it.

Click this to populate the main window.